v3.26.1
Loans, Borrowings and Bank Overdrafts - Additional Information (Detail)
₨ in Millions, ฿ in Millions, ৳ in Millions, ر.ق in Millions, ر.س in Millions, ¥ in Millions, £ in Millions, Rp in Millions, R$ in Millions, .د.ب in Millions, $ in Millions, $ in Millions, $ in Millions
 12 Months Ended
Jun. 23, 2021
USD ($)
Mar. 31, 2026
INR (₨)
Mar. 31, 2026
USD ($)
Mar. 31, 2026
SAR (ر.س)
Mar. 31, 2026
GBP (£)
Mar. 31, 2026
BHD (.د.ب)
Mar. 31, 2026
THB (฿)
Mar. 31, 2026
BRL (R$)
Mar. 31, 2026
IDR (Rp)
Mar. 31, 2026
QAR (ر.ق)
Mar. 31, 2026
MXN ($)
Mar. 31, 2026
CAD ($)
Mar. 31, 2026
BDT (৳)
Mar. 31, 2026
JPY (¥)
Mar. 31, 2025
INR (₨)
Disclosure of detailed information about borrowings [line items]                              
Borrowings | ₨ [1]   ₨ 167,874                         ₨ 161,817
Loans Borrowing And Bank Overdraft [member]                              
Disclosure of detailed information about borrowings [line items]                              
Loans, Borrowings and Bank overdrafts | ₨   94,860                         97,863
Line of credit [member]                              
Disclosure of detailed information about borrowings [line items]                              
Loans, Borrowings and Bank overdrafts | ₨   89,024                          
Line of credit [member] | U.S.Dollar [member]                              
Disclosure of detailed information about borrowings [line items]                              
Loans, Borrowings and Bank overdrafts     $ 432                        
Remaining borrowing capacity     $ 92                        
Line of credit [member] | Canadian Dollar [member]                              
Disclosure of detailed information about borrowings [line items]                              
Loans, Borrowings and Bank overdrafts                       $ 14      
Remaining borrowing capacity                       $ 14      
Line of credit [member] | Bangladesh, Taka [Member]                              
Disclosure of detailed information about borrowings [line items]                              
Loans, Borrowings and Bank overdrafts | ৳                         ৳ 175    
Remaining borrowing capacity | ৳                         ৳ 175    
Line of credit [member] | Japan, Yen [member]                              
Disclosure of detailed information about borrowings [line items]                              
Loans, Borrowings and Bank overdrafts | ¥                           ¥ 300  
Remaining borrowing capacity | ¥                           ¥ 300  
Line of credit [member] | Indonesia, Rupiahs [Member]                              
Disclosure of detailed information about borrowings [line items]                              
Loans, Borrowings and Bank overdrafts | Rp                 Rp 13,000            
Remaining borrowing capacity | Rp                 Rp 13,000            
Line of credit [member] | Indian Rupee [member]                              
Disclosure of detailed information about borrowings [line items]                              
Remaining borrowing capacity | ₨   27,524                          
Line of credit [member] | Saudi Arabia, Riyals [Member]                              
Disclosure of detailed information about borrowings [line items]                              
Loans, Borrowings and Bank overdrafts | ر.س       ر.س 120                      
Remaining borrowing capacity | ر.س       ر.س 75                      
Line of credit [member] | United Kingdom, Pounds [Member]                              
Disclosure of detailed information about borrowings [line items]                              
Loans, Borrowings and Bank overdrafts | £         £ 7                    
Remaining borrowing capacity | £         £ 7                    
Line of credit [member] | Bahrain, Dinars [member]                              
Disclosure of detailed information about borrowings [line items]                              
Loans, Borrowings and Bank overdrafts | .د.ب           .د.ب 1                  
Remaining borrowing capacity | .د.ب           .د.ب 1                  
Line of credit [member] | Thailand, Baht [Member]                              
Disclosure of detailed information about borrowings [line items]                              
Loans, Borrowings and Bank overdrafts | ฿             ฿ 5                
Remaining borrowing capacity | ฿             ฿ 5                
Line of credit [member] | Brazilian, Real [Member]                              
Disclosure of detailed information about borrowings [line items]                              
Loans, Borrowings and Bank overdrafts | R$               R$ 8              
Remaining borrowing capacity | R$               R$ 8              
Line of credit [member] | Qatari, Riyal [Member]                              
Disclosure of detailed information about borrowings [line items]                              
Loans, Borrowings and Bank overdrafts | ر.ق                   ر.ق 10          
Remaining borrowing capacity | ر.ق                   ر.ق 10          
Line of credit [member] | Mexican, Peso [member]                              
Disclosure of detailed information about borrowings [line items]                              
Loans, Borrowings and Bank overdrafts                     $ 35        
Remaining borrowing capacity                     $ 35        
Revolving credit facilities non-fund based [member]                              
Disclosure of detailed information about borrowings [line items]                              
Loans, Borrowings and Bank overdrafts | ₨   49,747                         49,634
Remaining borrowing capacity | ₨   ₨ 36,389                         ₨ 36,524
Unsecured Notes 2026 [member]                              
Disclosure of detailed information about borrowings [line items]                              
Borrowings $ 750                            
Interest rate 1.50% 1.50% 1.50% 1.50% 1.50% 1.50% 1.50% 1.50% 1.50% 1.50% 1.50% 1.50% 1.50% 1.50%  
Final maturity June 23, 2026                            
Unsecured Notes 2026 [member] | U.S.Dollar [member]                              
Disclosure of detailed information about borrowings [line items]                              
Final maturity   June-26                          
[1] Includes future cash outflow towards estimated interest on loans, borrowings and bank overdrafts, and lease liabilities.